PROJECT SUMMARY ABSTRACT Rates of neonatal abstinence syndrome have reached a staggering 6.5 per 1,000 births nationwide, creating an urgent need to identify how in-utero exposure to opioids and associated risk factors influence the developing brain. Rigorous scientific investigation of this topic requires addressing the lack of foundational knowledge of neurotypical development. However, characterizing brain development from the fetal period through infancy and early childhood, and particularly in marginalized populations affected by substance use, presents myriad challenges. This proposal brings together a multidisciplinary team with all of the expertise, experience, and institutional support to address these challenges in Oregon, a state particularly hard hit by the opioid epidemic. Through linking with three other sites, University of Vermont, New York University, and University of Pittsburgh Medical Center, the impact of this proposed Phase I project is significantly enhanced, and will provide critical information to support a national level effort for Phase II of the HEALthy Brain and Child Development Study. Aim 1 will develop, implement and evaluate innovative recruitment and retention strategies for high-risk populations. We will measure the feasibility, throughput, and demographic characteristics associated with different recruitment methods through a longitudinal survey of 150 pregnant women per site (n=600 across sites), half of whom use opioids during pregnancy. Aim 2 will address anticipated challenges of the planned Phase II study by implementing and evaluating a multi-site, standardized, research protocol including multimodal MRI of placenta, fetus, neonate and 24-month-old brain, biospecimen collection, and asessment of substance use, and other key domains. Feasibility, data quality, and efficacy of different assessment methods will be evaluated in a longitudinal sample of 20 mother-infant dyads (N=80 across sites, half of whom use opioids during pregnancy), and a cross-sectional sample of 5, 24-month- old children with a history of prenatal opioid exposure (N=20 across sites). Aim 3 will evaluate data acquisition, processing, and statistical considerations to maximize data quality, usability, and integration across sites. We will: (1) examine the efficacy of real-time motion monitoring for MRI at different developmental stages; (2) test time savings and data quality using new acceleration sequences; and (3) harmonize data and processing pipelines for fetal, neonatal and child MRI into a common framework based on the universal Brain Imaging Data Structure (BIDS). This project dovetails with several very strong lines of research at OHSU addressing substance use and the opioid epidemic (NIDA Clinical Trials Network), effects of pre- and postnatal exposures on brain and behavioral development (ECHO), placental and fetal development (UO1 Frias/Kroenke), and child and adolescent brain development (ABCD). Our existing and developing relationships with key governmental agencies, treatment facilities and nonprofits provides a strong foundation for addressing important legal and ethical issues, and growing a network for recruiting and retaining families for Phase II of this award.